(a) Field of the Invention
The present invention relates to an auto-restart circuit and auto-restart method, and more particularly, to an auto-restart circuit of a main stage that receives a power source voltage from an external source, and a method thereof.
(b) Description of the Related Art
FIG. 1 illustrates a power source device including a standby power stage 10 and a main stage 20.
A device such as a TV and the like, of which operation can be controlled by using a remote controller, includes the standby power stage 10 and the main stage 20.
The standby power stage 10 includes a standby integrated circuit (IC) 11, a primary coil (or a primary winding) 12, a standby power switch 13, a secondary coil (or a secondary winding) 14, a diode 15, an output capacitor 16, an auxiliary coil 17, a diode 18, and an auxiliary capacitor 19.
The standby IC 11 controls a switching operation of the standby power switch 13 connected to the primary coil 12. The primary coil 12, the secondary coil 14, and the auxiliary coil 17 are coupled at a certain winding ratio.
The diode 15 rectifies current flowing across the secondary coil 14, and the capacitor 16 is charged with the rectified current. The voltage charged in the capacitor 16 is a standby voltage Vo2.
The diode 18 rectifies current flowing across the auxiliary coil 17, and the capacitor 19 is charged with the rectified current. The voltage charged in the capacitor 19 is supplied as a power source voltage Vcc to a main IC 21 of the main stage 20 as well as to the standby IC 11.
A switch 30 is turned on according to a turn-on command received from a remote controller. When the switch 30 is turned on, the power source voltage Vcc is supplied to the main IC 21.
The main stage 20 includes the main IC 21, an upper switch 22, a lower switch 23, a resonance capacitor 24, a primary coil 25, a secondary coil 26, rectifying diodes 27 and 28, and an output capacitor 29.
As the upper and lower switches 22 and 23 are alternately turned on and off, an AC voltage is applied to the primary coil 25. Resonance is generated with resonance capacitor, leakage inductance and magnetizing inductance components of a transformer formed by the primary coil 25 and the secondary Coil 26, which causes current to be generated across the primary coil 25 and the secondary coil 26.
The rectifying diodes 27 and 28 rectify the current flowing across the secondary coil 26, and the output capacitor 29 is charged with the rectified current to generate a main output voltage Vo1.
A capacitor 31 smoothes an input voltage Vin. The standby power stage 10 and the main stage 20 receive the input voltage Vin from the capacitor 31.
If an abnormal state, such as an overload state, an over-voltage state of the output voltage Vo1, an over-voltage state of the input voltage Vin, an excessive temperature increase at the power source device, and an overcurrent flowing at the upper and lower switches 22 and 23 occurs, the main IC 21 is turned off and the upper and lower switches 22 and 23 do not perform a switching operation according to a protection operation for protecting the main stage 20. This is called a protection state. When the abnormal state is resolved, the protection state is finished and the main IC 21 restarts its operation.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.